There have been numerous attempts in the art to provide protective compositions for metal surfaces subject to destructive fire and high temperatures, and many of these compositions utilize clays and soluble sodium silicates. For example, U.S. Pat. No. 2,711,974 teaches a combination of sodium silicate with Kaolin clay as well as various metal oxides. Other teachings have combined special types of clay such as Kentucky Ball Clay with pigments such as titanium dioxide, see U.S. Pat. Nos. 2,785,091, 2,372,235 teaches a combination of an alkali silicate, a clay and a pigment. Such patent also discusses the two broad categories of clay, either Kaoline or Bentonite, both being soluble hydrated aluminum silicates, the Bentonite having more silica in proportion to the alumina. U.S. Pat. No. 2,549,516 teaches the art the manufacture of decorative structural panels for interior wall linings wherein the sub-coat contains sodium or potassium silicate, diatomaceous silica, quartz silica a Kaolinite type clay, water and pigments which may be titanium oxide, chrome oxide (green), iron oxides or ultra marine blue. The listed diatomaceous and quartz silicas poorly mix with water and the proportions taught do not provide flowable liquid compositions.
In addition, U.S. Pat. No. 3,207,624 discloses a composition which is intended to be used as an insulating coating in connection with negative resistance valve blocks. The coatings are shown to contain potassium silicate, zinc oxide, powdered mica, and Kaolin clay. However, it will be noted that the alkali silicate in the form of potassium silicate is present in an extremely high percentage by weight, and further, the composition disclosed therein is not intended to be flowable in the same manner as the composition provided by the present invention. Hence, the composition as shown in the above noted patent clearly cannot function efficiently as a fire and heat resistant coating as intended in the present invention.
Similar comments are applicable with respect to U.S. Pat. No. 973,557 which discloses an improved insulating material formed by mica fragments and which further include components such as glass, Kaolin clay, slate, silicate of soda and water. However, the composition disclosed therein, to be formed into a suitable insulating material, must be fired to a temperature of at least 300.degree. F., plunged into an insulating material which is absorbed into a mass, and then fired again at 400.degree. C. It is clearly apparent that the composition is not intended to be freely flowable once formulated and furthermore, it is clear that the coating is not intended to be in the form of a retrofit or flowable coating suitable for application on the working surface of the tool.
The present invention is, therefore, intended to provide a method which includes the use of a novel composition formed by a variety of ingredients present at certain ranges of percentages by volume which will afford to the working surface of the tools greatly improved fire and heat resistance characteristics.